What is the difference between var and const?

Answer 1

const is short for constant, which means the value cannot be changed. A value must be assigned to consts when declared.

Ex:

const pi = 3.14157;

var is short for variable, which means the value can be changed.

Answer 2

const is a variable in your code that you definitely don't want to change - for example, you want Pi to always be 3.1415

const myPi = 3.1415

If you try changing or reassigning this value, code won't work properly

var however can be changed, that's why it's called a variable.

const myPi = 3.1415;
myPi = 2; // error

var myPi = 3.1415;
myPi = 2; // this code works!